Evaporating unit for refrigeration



Oct. 9, 1934.

M. T. ZEIGLER EVAPORATING UNIT FOR REFRIGERATION Filed Nov. 23, 1933 2 Sheets-Sheet l SEEN Uw/MEDA JL/,ZDMELLZEJELLL Efwww? Oct. 9, 1934. M4 T ZEIGLER 1,976,101

liVAPUiATiNG UNIT FOR REFRIGERATION Filed Nov. 25, 1933 2 Sheets-Sheet 2 mi T JNVENTDR MaX/@LLI ZEJELEE.

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Patented Oct. 9, 1934 UNITED STATES 1,976,101 EVAPORATING UNIT FOR REFRIGERTION Maxwell T. Zeigler, Huntington Park, Calif., asslgnor to Central Ice and Cold Storage Com'- pany, Huntington Park, Calif., a partnership composed of John L.

Zeigler Zeigler and Cecelia M.

Application November 23, 1933, Serial No. 699,353

10 Claims.

This invention relates to improvements in evaporating units for refrigerating systems.

An object of the invention is to provide an improved evaporating unit which is of such construction as to be automatic in its operation and to be continuously defrosting. In most refrigerating systems it is highly advantageous that the evaporating unit require a minimum amount of space and to this end the evaporating chamber or evaporating space is supplied with ins, facilitating heat transfer. However, in most prior constructions the number of fins must be adequately spaced apart to prevent the intervening spaces being shortly lled with frost. The present evaporating unit is so designed as to enable thevns to be placed very close together so that a maximum number of ns can be used, and suitable provision is made for preventing the formation of frost thereon.

Another object of the invention is to provide a refrigerating unit which is so designed as to operate on the flood system principle wherein all pipe surface or surface defining the evaporating chamber or space is wet by the liquid refrigerant.

Another object of the invention is to provide an evaporating unit for refrigerating systems employing a forced draft for forcing air to be cooled through the unit, thus imposing a heavy load on the unit which is of such a design as to adequately take care of this heavy load.

A further object of the invention is to provide an evaporating unit for refrigerating systems which is of simple and durable construction having a minimum number of moving parts and which requiresfa minimum amount of attention and care in its operation.

The improved evaporating unit has been primarily designed to be used in ice vending machines but it may be employed wherever refrigeration is desired, such as, for example, cold storage rooms, electrical refrigerators, and the like.

With the foregoing and other objects in view, which will be made manifest in the following detailed description, and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Fig. 1 is a view in side elevation of the improved evaporating unit, parts being broken away to illustrate internal construction.

Fig. 2 is a vertical section through the evaporating unit.

Fig. 3 is a vertical section on an enlarged scale through the lower portion of the unit.

Fig. 4 is a horizontal section taken upon the line 4 4 upon Fig. 3.

Fig. 5 is a horizontal section taken upon the line 5-5 upon Fig. 3.

Referring to the accompanying drawings, wherein similar reference characters designate similar parts throughout, the improved evaporating unit comprises an inner tube or shell 10 having a closed top l1 and an annular bottom 12. Within this tube or shell there is disposed an upstanding steel tube 13 having a dished head 14, thus forming a type of false or elevated bottom extending upwardly for a considerable distance within tube or shell 10. The presence of the inside tube 13 is optional and may be dispensed with. Its purpose is to occupy space inside of the shell 10 so as to cause the small volume of liquid normally disposed within the shell to be in the form of a relatively tall column as shown. Between tube 10 and tube 13 there is disposed a third tube 15 which divides the interior space within tube or shell 10 into a reservoir lwhich is surrounded by an evaporating chamber or space 17. This third tube is held concentrically with respect to tube 10 by means of suitable spacing rods 18, clearly shown on Figs. 4 and 5. The reservoir 16 is in communication with the evaporating space or chamber at top and bottom, these points of communication being located both above and below the normal level of liquid in the reservoir 16. Preferably, the bottom edge of tube l5 is serrated or notched, as indicated at 19, although this particular arrangement is not essential. Likewise, it is not essential to have a serrated top edge indicated at 20 although when a serrated edge is used the notches act somewhat as weirs, as will hereinafter be explained.

A cylindrical shield 21 is welded or otherwise secured to the top 11 and extends downwardly a considerable distance below the top edge of tube 15. An inlet pipe 22 leads from a suitable source of liquid refrigerant, such as from a compressor, and a holder which delivers a liquid refrigerant. This pipe communicates with the bottom of the evaporating space or chamber 17. An outlet pipe 23 extends upwardly through tube or pipe 13 through its dished head 14, where it is Welded in place, and up into the top of reservoir 16 so that its entrance is disposed within shield 21. A plurality of rotating metal heat collecting ns 24 are welded or soldered or otherwise secured to the exterior of tube 10 and radiate outwardly. These fins, as shown in Figs. 4 and 5, may be positioned very close together. Their outer ends are welded, soldered, or otherwise secured within an outer shell 25. On the tops of these vertically extending ns there is positioned a spider 26 on which is mounted an electric motor 27, the rotor shaft of which carries a fan 28. 'I'he spider also provides an annular trough 29 designed to receive a deliquescent salt, such as calcium chloride, indicated at 30. The bottom of the trough is perforated, as indicated at 21, and beneath this trough there is preferably positioned a layer of hardware cloth 32, under which there is a layer of felt 33. The bottom edges ofthe vertically extending ns 24 are preferably beveled off as indicated at 34 so that they terminate adjacent annular bottom 12. A spanning member 35 is secured across the interior of tube 13 and suspends by means of a rod or pipe 36 a collecting pan 37 from which may lead an outlet pipe 38. An oil drain pipe or blow off 39 is connected to the very bottom of the evaporating space or chamber where it communicates with the bottom of reservoir 16.

The operation and advantages are as follows:

On delivering a liquid refrigerant through pipe 22 the reservoir 16 and evaporating space tend to ll as the reservoir and evaporating space are in communication. The heat of liquid within the reservoir tends to balance the heat of liquid within the evaporating Space. However, as the refrigerant is highly volatile it receives heat from surrounding air collected by the various fins 24 with the result that in the evaporating space, which is quite thin, the liquid quickly tends to boil. Consequently, in this space a frothy liquid immediately forms and, consequently, because of this frothy liquid having a very low density the heat of liquid within the reservoir is capable of balancing a much higher column of boiling liquid within the evaporating space. The result is that the liquid in the evaporating space receiving its heat from outside sources boils up to the top of the evaporating space and boils over through the weirs or notches indicated at 20 on the top of tube 15. As it falls down in the reservoir the vaporized liquid or gas separates from the remaining liquid, the remaining liquid collects in the bottom of the reservoir, the gas is removed from the unit through outlet pipe 23 which returns it to the compressor for recompression and re-delivery to the unit as a liquid through pipe 22. Entry of liquid into outlet pipe 23 along with the gas which might cause compressor difficulties is effectively prevented by the surrounding shield 21.

The electric motor 27-is supplied with any suitable source of electric current and surrounding air is forcibly blown downwardly through the radiating fins 24. As will be noted upon Figs. 4 and 5, these ns may be positioned very close together, a feature which would be impossible unless some provision were made to prevent the formation of frost between these ns. As the air is drawn or blown downwardly through the trough 29 and through the lumps of calcium chloride or equivalent deliquescent salt therein the moisture in the air is suflicient to cause this salt to slowly deliquesce, forming a brine which flows downwardly through the vapertures in the bottom of the'trough, and the brine is .distributed to the top edges of the ns by the hardware cloth and the layer of felt. This brine formed by the deliquescent calcium chloride has the faculty of spreading over the surfaces of the ns, wetting the surfaces of the ns, and the exposed exterior of tube 10 therebetween, throughout. The presence of this brine prevents the formation of any frost whatsoever on the fins. It does not permit the formation of any frost with the brine channeling its way through the frost but, instead, because of its extreme spreading qualities prevents the formation of any frost whatsoever on the fins. As the brine flows downwardly over the surfaces of the fins it finally reaches the beveled edges 34, causing it to collect on bottom 12, from which excess brine drips into collecting pan 3'7. This brine is then removed from outlet pipe 38.

From the above described construction it will be appreciated that the only moving parts of the improved evaporation unit are the rotor of the motor and the fan that it carries. Consequently, there are no parts to get out of order. The unit may be made relatively small, yet it has a high capacity in that a very large volume of air can be easily and quickly cooled and kept in a refrigerating condition. It will be noted that the entire pipe surface on the inside of tube 10 is Wet by the liquid, thus utilizing the entire capacity of this pipe for refrigerating purposes. As the evaporating space or chamber surrounds the reservoir it effectively acts as a heat insulator insulating the body of liquid within the reservoir against any tendency to evaporate or volatilize. Where the refrigerant is a gas or liquid in which lubricating oil is relatively soluble, such as, for example, ammonia, the lubricating oil picked up in the compressor tends to collect in the bottom of the reservoir and the evaporating space. This lubricating oil can be withdrawn by opening valve 40 periodically in pipe 39 and the lubricating oil thus removed from the system while the unit is in operation. Where other refrigerants are used in which lubricating oil is more soluble it may be necessary to shut inlet pipe 22 and exhaust the remaining refrigerant through the system. In so doing the remaining refrigerant distills itself, leaving behind lubricating oil in the bottom of the reservoir and the bottom of the evaporating.

space.

When the refrigerant has then been exhausted from the unit, valve 40 can be removed to thus drain off the lubricating oil which has been left in the unit. The removal of lubricating oil from the unit is necessary only at periodic intervals and depends somewhat upon the condition of the compressor used and to the extent which it contaminates the refrigerant with lubricating oil. Aside from the removal of lubricating oil from time to time, the only other care that the unit requires is the refilling of trough 29 with calcium chloride or equivalent deliquescent salt. This in the( course of time must be refilled.

I nd that the above described evaporating unit has a very high efllciency for` its size as compared with other evaporating units. The entire construction can be made relatively light so that no special foundation or support is necessary as is now the case in large cold storage rooms to support the many feet of pipe or cooling coils. The construction, by having a forced draft, can handle alarge quantity of air and quickly reduce its temperature to the desired point. Also, circulation of air is, maintained through the entire cold storage space, which is highly advantageous. A1- though frost is prevented from being formed between the various fins, moisture in the air circulated through the evaporation unit is withdrawn in that it is absorbed by the brine and carried with the brine to the bottom of the fins where it drips with the brine into the collecting pan 37 and is removed from the cold storage space` entirely.

I find that this unit is highly advantageous nordici when it is employed for maintaining ice vending machines at a desired refrigerating temperature. When so used it is merely necessary for an inspector to periodically visit the machine, refill the trough with a deliquescent salt and from time to time remove the collected oil.

Various changes may be made by those skilled in the art in the construction and arrangement of parts without departing from the spirit or scope of the invention as dened by the appended claims.

I claim:

l. An evaporating unit for refrigerating systems comprising means providing a reservoir for volatile liquid, means providing an evaporating space around the reservoir which is in communication with the reservoir above and below the normal liquid level therein, means for supplying the evaporating space with liquid, means for removing gas from the reservoir above the liquid level therein to be compressed and returned to the evaporating space asa liquid, and iins projecting outwardly vfrom the evaporating space providing means.

2. An evaporating unit for reirigerating systems comprising means providing a reservoir for volatile liquid, means providing an evaporating space around the reservoir which is in communication with the reservoir above and below the normal liquid level therein, means for supplying the evaporating space with liquid, means for removing gas from the reservoir above the liquid level therein to be compressed and returned to the evaporating space as a liquid, and iins projecting outwardly from the evaporating space providinCr means, and means for distributing a brine over the hns.

. 3. An evaporating unit for reirigerating systems comprising means providing a reservoir for volatile liquid, means providing an evaporating space around the reservoir which is in communication with' the reservoir above and below the normal liquid level therein, means for supplying the evaporating space with liquid, means for removing gas from the reservoir above the liquid level therein to be compressed and returned to the evaporating space as a liquid, ins projecting outwardly from the evaporating space providing means, and means for distributing a brine ci a deliquescent salt over the ns.

e. An evaporating unit for reirigerating systems comprising means providing a reservoir for volatile liquid, means providing an evaporating space around the reservoir which is in communication with the reservoir above and below the normal liquid level therein, means for supplying the evaporating space with liquid, means for removing gas from the reservoir above the liquid level therein to be compressed and returned to the evaporating space as a liquid, means shielding the gas removing means from the entry of liquid, and hns projecting outwardly from the evaporating space providing means.

5, An evaporating unit for refrigerating systems comprising means providing a liquid reservoir surrounded by an evaporating space, ns projecting outwardly from the evaporating space, the reservoir and evaporating space being in communication above and below the normal level of liquid in the reservoir whereby the liquid in the evaporating space may boil over into the reservoir, and means for creating a current of fluid to be cooled between the fins.

6. An evaporating unit for reirigerating systems comprising means providing a liquid reservoir surrounded by an evaporating space, ins

projecting outwardly from the evaporating space, the reservoir and evaporating space being in communication above and below the normal level of liquid in the reservoir whereby the liquid in the evaporating space may boil over into the reservoir, means for creating a current of fluid to be cooled between the' fins, and means for distributing a brine of a deliquescent salt over the fins.

'7. An evaporating unit for refrigerating systems comprising means providing a liquid reservoir surrounded by an evaporating space, ns projecting outwardly from the evaporating space, the reservoir and evaporating space being in communication above and below the normal level of liquid in the reservoir whereby the liquid in the evaporating space may boil over into the reservoir, means for creating a current of fluid to be cooled between the fins, and means for providing a holder for a delinquescent salt over the iins adapted to have a current created therethrough to cause the salt to deliquesce and be distributed upon the ns.

8. In an evaporating unit for refrigerating systems, means providing a central reservoir surrounded by an evaporating space, the evaporating space being in communication with the reservoir near its top and bottom, means for supplying a volatile liquid to the evaporating space whereby upon evaporating, it may boil over into the reservoir, means for withdrawing gas from the top of the reservoir to be compressed and returned to the evaporating space as a liquid, vertically extending ns on the outside of the evaporating space, a blower for blowing an air blast between the ns, and a holder for a deliquescent salt arranged over the ns so as to have an air current induced therethrough to cause the salt to deliquesce and its brine to be distributed over the ns to prevent the formation of frost thereon.

9. In an evaporating unit for refrigerating systems, means providing a central reservoir surrounded by an evaporatingspace, the evaporating space being in communication with the reservoir near its top and bottom, means for supplying a volatile liquid to the evaporating space whereby upon evaporating, it may boil over into the reservoir, means for withdrawing gas from the top of the reservoir to be compressed and returned to the evaporating space as a liquid, vertically extending ins on the outside of the evaporating space, means enclosing the fins, a blower for blowing an air blast between the ns, and a holder :for a deliquescent salt arranged over the ins so as to have an air current induced therethrough to causo the salt to deliqucsce and its brine to be distributed over the ns to prevent the formation ci frost thereon.

l0. In an evaporating uint for reirigerating systems, means providing a reservoir and an evaporating space arranged so as to largely insulate the reservoir from heat, the evaporating space being connected to the reservoir near its top and bottom, means for supplying the evaporating space with a volatile liquid so that upon evaporation it may boil over into the reservoir, means for withdrawing gas from the reservoir near its top to be returned to the evaporating space as a liquid, ns radiating from the evaporating space, means enclosing the iins, a blower arranged centrally over the reservoir and arranged to create an air current through the ns, a holder for a deliquescent salt arranged varctmd the blower, and `means for distributing brine formed by the salt over the ns.

MAXWELL T. ZEIGLER. 

